Methoprene and synergized pyrethrins as aerosol treatments to control Plodia interpunctella (Hübner), the Indian meal moth (Lepidoptera: Pyralidae)

Aerosol insecticides (also known as ULV or fogging treatments) delivered through an ultra-low-volume application system, are available commercially to control insect pests such as Plodia interpunctella Hübner, the Indian meal moth. However, little is known about the susceptibility of eggs of P. interpunctella to aerosol insecticides applied in active field sites. We conducted several trials by exposing eggs of P. interpunctella to synergized pyrethrins, alone and in combination with the insect growth regulator methoprene. Eggs in diets and packaging materials containing the food products were directly exposed to the aerosols. There was significant variation among the food products, as assessed by adult emergence from exposed eggs, but in general there was no difference in adult emergence from eggs exposed to a 1% versus a 3% pyrethrin formulation when methoprene was included. There was no difference in efficacy between diets and diet packages placed in open areas versus areas that were in some way obstructed to the aerosol. Adult emergence was generally reduced in the treatment combinations compared to untreated controls. A partial budget analysis indicated that the combination treatment of 1% pyrethrins + methoprene represented the lowest risk, lowest cost, and would seem to be the optimum combination. Results show that field applications of aerosols could be used to control P. interpunctella in storage facilities.